In the medical field, there is a known optical fiber scanner in the related art that scans illumination light on a subject by causing illumination light to emerge from an optical fiber while vibrating the optical fiber at high speed using a piezoelectric element (for example, see Patent Literature 1). The optical fiber scanner described in Patent Literature 1 is provided with a tube-shaped piezoelectric element (PZT tube), four electrodes which are arranged on the surface of this PZT tube with equal gaps therebetween in the circumferential direction, and an optical fiber that is inserted inside the PZT tube, and the distal end portion of the optical fiber is fixed to the PZT tube by a coupling member.
In the optical fiber scanner described in Patent Literature 1, when the PZT tube deforms in a bent shape, a force in a perpendicular direction acts on the optical fiber via the coupling member, and this force causes the optical fiber to undergo bending vibrations. Thus, by combining the bending vibrations occurring in two orthogonal directions in the optical fiber, it is possible to make the distal end of the optical fiber vibrate in a spiral fashion and to two-dimensionally scan the illumination light.